HomematicIP + MQTT
HomematicIP room thermostats (living room, bedroom, home office) report temperature and humidity into the smart home dashboard via a small, deliberately low-tech bridge: Home Assistant → MQTT → InfluxDB.
Why this path, and not a direct integration
A dedicated HomematicIP-to-MQTT exporter used to run as a standalone Docker container, but the underlying Python library lost compatibility with HomematicIP's cloud API and hasn't been maintained since 2022. Home Assistant, on the other hand, ships an actively maintained HomematicIP Cloud integration — so instead of chasing a broken exporter, the bridge now runs as native Home Assistant automations that simply republish sensor state changes to MQTT.
How it works
- Home Assistant automations trigger on thermostat state changes.
- Each automation publishes the current temperature and humidity to a per-room MQTT topic.
- A small .NET background service subscribes to those topics and writes the values into InfluxDB, tagged by room and sensor type.
- Grafana reads from InfluxDB for the temperature/humidity dashboards.
Why this is worth documenting
- No extra Docker container or unmaintained library dependency.
- Cloud-API changes are absorbed by Home Assistant's own maintainers, not by custom code.
- The MQTT bridge is just configuration (automations), not a service that needs its own uptime monitoring.